Shower head



E. c. WEBB SHOWER HEAD Feb. 17, 1959 Filed June 21, 1956 I Z V 4 42 40 i & W J5 3 34 I011 2 Sheets-Sheet 1 INVENTOR.

Aim 5:7 e W563,

Feb. 17, 1959 Filed June 21, 1956 E. C. WEBB SHOWER HEAD 2 Sheets-Sheet 2 HZM larly to a shower head-for domestic bath showers.

United States Patent 12,074,001 vsnownn nnan I Ernest C.';Whb, Bayvillage, 'Ohio swimmer-June :n, 1956, Siial No. 592957 8 Claims. c1. 299-441 This invention relates to a shower :head and particu- Co'nventional "shower heads now in use .in domestic shower baths do not produce substantially clear, non-turbulent, directionallyaccurate and stable streams "or jets of water. Instead, there is a wide variation in the consistency .and cross secti'on of each individual -jet at dilferen't times and .at diflerent locations along its length. --Ditfrences in water pressure and the resultant rate of discharge aggravate these variations in the consistency and compactness of. the jet atudifierent locations along its length and also variations in the degree of turbulence and =in=the overall directiomofiflowordischarge.

Generally, there are widevariations in *thevstreams or jets relative to each other even when the'water pressure isconstant. For example, the jets differ from each other in cross section, they are diflerently aerated, all are turbulent and the turbulence of each is different from that of the others, they do not define a regular divergent pat tern but instead are "directionally unstable and irregularly directed. Very rarely do they maintain their compactness and 'clearness for any appreciable distance beyond their orifices but instead each tends to splutter, spread and break up intomyriad small dropsand lose its'iclentit-y.

Furthermore, such shower heads accumulate deposits of carbonates and foreign :miatter from the water line. These deposits fully or partially clog the orifices thus causingthe orifices :to discharge erratically.

Some of the conventional nozzles in use today include a spray'capwhich-is provided with (orifices which are distributed over its face in a regular ipattern and which are arranged toi'diverge outwardly with respect to each other in the general direction of discharge, thus providing 'a wider pattern at the-point of application on'the body.

In others the orifices are =formed'by a central plug having a serrated peripheral wall which is juxtapose'd against a smooth surrounding peripheral wall of the body, the walls defining therebetween an annular row of orifices; In general, the orifices of these pri'orsn uctures' are rno're in the form'of cylindrical passages or nozzles havingan appreciable length. They are formed generally by'drilling, broaching or like cutting operations; It appears that slight burn or variations in surface conditioninherently result from the machining operations arm wane these often cannot be detected except with astrong magnifying glass, they are snlficiently large to change materially the characteristics of the stream of water which issues from the particularorificeor nozzle, causing turbulence, 'dir'ectional instability, and other variations. *It appears that the most critical part of such an orifice or nozzle is'i'ts entrance end.

If the orifice or nozzle has appreciable length another critical Part is the passage between the entrance end-and the discharge end. It is necessary for providing a smooth, parallel or non-turbulent and directionally and dimensionally stable flow that the :inlet end of the orifice be extremely precise and that the passage through the orifice be such that :its peripheral Wall do'esnot-engage the jet or stream of water and interfere wiih it' in'any way during its pa'ssagefrorn the orifice -inlet throug h 'the" outlet. v The principal objects of the present-invention are to Patented Feb. .17, .1959

, 2 provide a simple and efiect'ive shower head which inay be economically manufactured and serviced, which operates to discharge from the individual .nozzles jet-s or streams of water which are clear, smooth, non-'turbulent-dimensionally stable in cross section, and directionally stable under all normal operating pressures.

Another object is to provide a means by whichjets of different crosssection may beprovidedto.meetndiifer ent conditions or desires of the user.

Another object is to provide a shower head on which the deposition of carbonates and foreign matter frbm -the water is greatly reduced, and as to which particles =91? flalces of such deposits are prevented-from reaching the shower orifices, or, if 'by chance they do reach the orifices, they can readily be cleaned and removed.

Another object is to provide a shower head having simple and etfectiveorifices of which the inletedgesere circular and very accurately formed, and which are free from burrs, surface roughness, and the like, as a=-result of which cylindrical, substantially non-turbulent streams are discharged accurately directionally;

Another object resides in the provision of an orifice plate which may be formed in flat condition with ;apin: rality of orifices in which the axes are parallel with each other but which, when installed, is warped so :as to be concave toward the oncoming water as a result ofwhich the axes of the orifices are divergent .in the direct-ion of flow of water theretlirou'gh.

Another object is .to' provide in the shower head a bafile means -for reducing the turbulence and obtaining more nearly a smooth parallel or laminar 'flow of-the water preparatory to its entry into the orifices.

Another object resides in the manner in which the shower .head is arranged so that the-cap can be removed, the parts cleaned, different orifice plates installed selec tively, and the parts effectively replaced in sealed relat'ion so as to assure that all of the-water'entering' the he'ad reaches the orifices in a substantially non-turbulent condition.

Other objects and advantages will become apparent from the following description wherein 'refere'nce'iis made to the drawings,.in which: r

Fig. 1 is a perspective view-of the shower head-embody ing the principles of the present inventions;

Fig. 2 .is a front elevation of the shower head .illus-' trated in Pig. 1, taken in a direction axially of the head, part thereof being broken away for clear'ness in illus tration; v i

3 is a cross sectional view taken on thei'line of Fig. 2;

Fig. 4 is an exploded view, partially in section, showing the various parts of the head illustratedliii Fi 'gs. *1= through 3 and the order in which they are assembled; and i Figs. 5 and ;6 are enlarged fragmentary cross sectional views illustrating modifications of'the orifices or nozzles of theshoWer head.

Referring first toFigs. 1 through 4, the 'headc'omprises' a hollow body 1 to which :is secured an :inlet fitting 2 which, in turn, isadapted to be-secured to a'iittingF of a suitable supply pi e L for supplying water into the" which lead, in succession, from the inner end of the fitting 2 to the bore 3. The bores 4 and 5' have side wallswhich are divergent 'in the direction or flowo'f thewater.

.At its outer or discharge end, -'the"body- 1 is closed By a suitable "detachable'ca'p 6; Thecap is detachably'ab c'ur'edori the body by-'means' of suitable cooperating lugs 7 on the cap and cooperating lugs 8 on the body. The lugs 7 and 8 are arranged so that the cap can be pressed against the open end of the body with the lugs out of registry and installed and drawn tightly against the outer end of the body by turning the cap through a very small angle about the axis of the bore 3.

' The cap 6 is provided with a plurality of passages 9 corresponding in position and number to the jets or streams of water to be discharged by the head.

Disposed at the inner face of the cap 6 is an orifice plate 10 which is provided with a plurality of orifices 11. The plate 10 is installed 'at the inner face of the cap 6 with the orifices 11 in registry with the passages 9 of the cap.

The orifices 11 of the orifice plate 10 are very precisely and accurately formed with smooth circular entrance edges. They are less in diameter than the passages 9.

In order to eliminate the possibilities of burrs or roughness'on the entry edges of the orifices 11 or at any locations along their lengths, the orifices are preferably formed in the plate by punching. For example, the punch and its companion die should be very accurate, with a clearance of less than .0005 of an inch. The orifices are formed with the plate 10 flat and with their axes parallel to each other and at right angles to the plane of.

the plate.

The diameter of each orifice preferably is about .027 of an inch for a fine jet and .040 of an inch for a somewhat coarser jet with the plate 10 preferably .010 of an inch or less in thickness, though the plate may be somewhat greater in thickness, if desired.

A suitable positioning pin 12 is provided in the orifice plate 10 and is adapted to engage a suitable socket 13 in the cap 6 for holding the plate 10 in the proper circumferentially rotated position about the axis of the cap. The cap is provided with an internal annular shoulder 14 which engages the periphery of the plate 10 so as to center it properly transversely of the cap.

As mentioned, it is critical that the inlet edge of the orifices 11 be precise and accurately formed and that they and the walls of the passages through the plate 10 be smooth and free from burrs. When so made, if water having a smooth or approximately parallel flow is forced against the inner face of the plate 10, it will issue through the orifices 11 as substantially clear nonturbulent jets which are stable directionally and stable dimensionally in cross section. In order to obtain this effect, however, it is necessary that the jets be not disturbed by engagement with any extraneous obstruction after they issue from the orifices. Also, it is desirable that the jets diverge in a regular pattern.

. Accordingly, the inner face of the cap 6 is made con-' cave toward the oncoming stream of water in the head. Preferably it is made curvilinear or spherical, as illustrated. When the water is introduced against the back ofthe plate 10, the pressure of the water forces the plate against the inner concave face of the cap 6 and the plate 10 therefore becomes concave toward the oncoming water. This shaping of the plate 10 changes the direction in which the axes of the orifices extend with respect to each other, causing them to diverge away from the head.

The passages 9 in the cap are made with their axes parallel as it is much more economical to drill or mold a group of parallel passages than to drill them at divergent angles. However, the passages 9 are sufliciently large in cross section throughout their lengths so that, when their inner ends are coaxial with the orifices 11, the jets from the orifices do not impinge on the walls of the passage even though the passages 9 and orifices do not have parallel axes.

I Each passage 9 must be of sulficiently small diameter so-that the part of the plate 10 aligned therewith is held rigid and is not deflected or warped by water pressure.

"Asmentioned, it is desirable that the water reach the orifices in as near a smooth, parallel flow, free from turbulence, as possible and further that foreign matter be prevented from reaching the orifices. Accordingly, an interponent 16 is provided. The interponent 16 is in the form of a disc and has a plurality of closely spaced passages 17 distributed uniformily radially of the disc, the passages 17 preferably being parallel to the axis of the head or inlet fitting 2. In order to assure that all of the incoming water passes through the interponent 16, the interponent is provided with an annular flange 18 at its discharge end. To provide an effective seal between the body 1 and cap 6, between the body and plate 10, and between the body 1 and the interponent 16, and the interponent 16 and plate 10, the interponent is provided with an external annular flange 19, the body, near its open end, is provided with internal flanges 20 and 21, and the cap is provided with an internal flange 22. These flanges are all positioned relative to each other so that a single 0 washer 23, of circular cross section, can be used for effecting a seal between the parts mentioned. As illustrated in Fig. 3, it is to be noted that when the washer 23 is pressed firmly into place by the cap 6 it engages the shoulders 19 and 20, thus providing an efiective seal between the interponent 16 and body 1 so that all of the water entering the body from the fitting 2 is constrained to pass through the interponent. Again, the O washer bears against the margin of the plate 10 thus providing an effective seal between'the discharge end of the body 1 and interponent 16 and the periphery of the plate 10 so as to constrain all of the water discharged through the interponent to pass through the plate 10. Further, the washer 23 effects a seal between the shoulders 19 and 20 of the body and the shoulder 22 of the cap 6. In order to reduce further and substantially eliminate any turbulence, the interponent includes a screen 24 arranged on the inlet side of the interponent 16. The screen 24 is of fine mesh and may be one or more layers thick. It'is suflicient to break up the localized lateral currents and turbulence and cause the flow of water approaching the passages 17 to be more nearly axially directed and more uniformly distributed radially of the interponent 16. Additionally, to reduce turbulence, the interponent is provided with a deflector 25 which is coaxial with the inlet passage of the fitting 2 and which is shaped at its inlet face to intercept the stream of water issuing from the fitting and deflect it as annular sheet back toward the inlet end of the body and outwardly toward the wall 4.

The deflector 25 may be secured to the interponent 16 by means of a bolt 26 so as to form a part of the interponent and to hold the screen 24 in proper position. As mentioned, each shower head is provided with a plurality of plates 10 destinguished from each other by the size of their respective orifices 11. These plates can readily be removed for cleaning and the like or for changing to provide different sizes of jets.

It is desirable, however, to retain the interponent 16 and screen and washer in the head while changing the plates 10. For this purpose spring clips 27 are provided. The clips 27 are secured in suitable grooves 28 in the side of the interponent 16 and are fastened in place by means of rivets 29. Each clip has a raised shoulder 30 near its inner end so arranged as to frictionally press firmly against the inner wall 3 of the body 1 and frictionally secure the interponent and screen therein. At its outer end each clip is provided with an outwardly concave holding portion 31 which is adapted to engage the washer 23 and hold it firmly against the shoulder 21 of the body. In the form illustrated, two such clips 27 are shown but, if desired, more can be disposed about the periphery of the interponent. The clips hold the interponent snugly in place against the forces of gravity but witha force so limited that the interponent can be forced out of the body by pressure of the water when the water is turned on to provide a substantial flow with the cap 6 removed.

In; operation; the ..cap 6..is remo.ved;and.-the plate with the desired size orifices is installed in the cap, being centered therein by the. annular .shoulderr14. and properly positioned. circumferentially Ofithe, cap;byuthe--.pin 12 engaging the socket 13.

In .this condition the orifices 1150f theplate 10 are alignedwith. the passages 9,in :the, cap 6.:. Thecap is then pressed against. the. body -1 andugivenaqturn of a few degrees, whereby the-lugs. 7' and 8 draw itafirmly into...sealing. engagement with the. washer 23.: This securesthe. cap 6-in. place and. .places the-Washer-ZS under sufficient stress to prevent leakage between cap .and body. and. to .assure that. all water.v entering; the body passes throughthe screen..24, the. passages 17., andithe orifices I1 of the .platev 10. while at the same: time preventing; any of the. water from passing;otherwisev fromaone. side of the. interponent to the other. or from onev 1 side of the p1ate..10 to the. other.

The. washer 23 is sufficiently yieldable and resilient so that. it .does' not prevent .the slight radial movement of theimarginiofthe plate 10. as-pressure of, the water defiects thegplate 10. and warps it into. firm face to.-face juxtaposition withthe inner, faceof the cap; 6;

The water reaches the. inner face. of...the plate '10 in. an approximately; smooth parallel or'laminar-unidirectional.

flow parallel to'the: axis. of. the body Since; the inlets of the. orifices 11 areaccuratelyv formed, the water is divided into a plurality of jets which pass from the inlets of. the orifices .11: out of. the. outletsof the. passages. 9 without: touching the walls' ofthe. orifice passages 11' or=of .tlie passages9- These jets are-relatively clear as they leave-the head 1. They; strike the body of the user. o.the shower, under normal conditions, as. well defined, relatively solid, high velocity streams. which". are accurately directed- Asa result, avery eflective and; forceful; needle-like eflfect is produced.

If desired, insteadof the orifice: platev described, -modifiedforms of the cap may-beused, asillustrated in Figs; 5 .and. 6,,respectivelyi InpFig, 5 there isshown a cap 33 .which is,.similar. in generalftothe capo-heretofore. described. However, insteadof the passages 9 thecap 33is provided with a plurality: of individual. nozzles. Each ofthese nozzles isin. the form'of a short tube 34 which is firmlysecured: tothe capjafiand is.-open.at one endon-theinside of the cap. Each time 34 extends a short distance beyondthe outer face ofthe cap, and isprovided at its ,outerend with an individual. orifice plate 35. havingan orifice36- therein... The. orifice plate -may; bean, integral part. of. .the tube 34, or, if desired, it may be a'separate plate.- inwhich latter-case a suitable sealing ;cap' 37 may be permanentlysecured to the. outer end of the-.tube 34 for holding the orificeplate implace. Each tube has-a pas sage.38 of sufficient diameterso that the jet issuingfromthe orifice 35 doesnot strikethe walls of ,the passage-38. In this form of the invention, ifkdifferent-sizes of jets. are, desired, separate caps, each :Wllh ditferentorific'es or nozzles, are provided.

In. Fig. 6-therev is illustrated a cap; 40 similar to the cap fiexcept that the passages 41, instead of extending. entirely through the cap terminate-near the innerlface of the cap. and a thin integral web 42 isleft. at the, base of each passage 41.. Thistwebprovides; ineifect, an in.- tegral orifice plate for its associated passage 41. The web, in turn, is provided with an orifice-43.. This modification is notasrdesirableaas the preferredw form of the invention described inconnection with Figs. 1 through 4 in that directional punching-of the" orifices 43 is required aseach orifice has its axis divergentwith respect. to the axes-of the others in the direction of discharge. Eurthermore, if any one orifice is improperlymade during manufacture,- the entire cap must be scrapped.

It is apparent from-the foregoing; description that the shower head described is very effective, providesclear jets which. are. stable..,din 1ensionally. incross. section and directionally, .andwhich [aresubstantially free from ;tur bulence. 'The shower. head can be. made veryeconornh cally, The. orifice plate lllpmay. bemade of any, thin material, such as stainless, steel copper, brass, ,orthelike, or organic plastic. material,. such as is. commonly termed plastics. The plastics are particularly desirable,, not only .for the ,plate 10 butfforthe body, interponent, and cap, in ;that the. tendency. for. carbonates. and the like.,to form, deposits thereon .is :greatly reduced oreliminated; If depositsare formed,..th.eycan beremovedmore .readily from plastics .thanirom metal.

SeveraLadvaritages result from making, the. plate. 10 very, thin, First, the .orifices. can be-formed more.accurately therein. Also,,the..length,of thepassage from theinlet to the outletofjeachorifice is so v.shortthatitis almost impossiblev 'for, foreign matter to lodge .inthem anddanger,oflimpingement of thejet against thepassage wall is eliminated... Furthermore, ,a thin .platecancon, formto the. curvatureof the rear-face. ofthe cap 6. at lower waterpressures. than. can. a thick plate.

Havingthusdescribedmy invention, I claim:

1. 'A shower head comprising a hollow body adapted forvconnection to a shower, bathwater supply pipeand. having an ,inlet passage andv a discharge passage, a cap covering the outlet of-.the, discharge passage and having a multiplicity of passages therethrough from its innerface. to its outerface, an orifice plate of thin relatively stiff but flexible sheet materialoverlying the inner face. of the cap andhavinga-plurality of water jet orifice-s. therein which have smooth entering edges and which are aligned with. thepassageof the .cap, the. cap; passages being suf-' ficiently greater. in ,cross section than the-orifices so that, the jets; from the orifices, sit-shower bath water supply pressures suflicient to cause the water to issue .as jets.

fromthe orifices, respectively, can pass, through associated passages in thecap freeffr'om contact with, the peripheral walloftheir assoeiatedflpassages-in the cap, saidnplate andcap being readily detachable from the body, the innerface of said cap being in ,theformof a shallow con-. cavity, said.,plate.being, normally flat and.unfiexed, the. axes. of thelorifices being parallel to each. other. when the plate is fiat and unflexed,. the. plate being sufficiently flexible -.to be flexed by said householdwater pressure, while the plate is mountedin .the body, outwardly against.

the inner face of the capand become concaveinwardly,

of; the body when the: shower head is in operation,

whereby the axes of at least somev of theorifices-become divergent from each,other;in a direction away from thebody.

2. A showerhead comprising a hollow body adapted for connection to ashower bathwater supply pipe and having aninlet passage and a. discharge passage, a detachable cap covering the. outletof the. discharge passage :and having a multiplicity of passages therethrough. from itsinner faceto its outer face, an orifice plate ofthin relatively stiif but flexible sheet material overlying the inner face of the cap and readily detachably from the body. andhavinga'plurality ofwater jet orifices therein which have burrle'ss, smooth entering edges and which are aligned with the passages of the cap, said orifices being respective' to the passages in the cap, the cappassages being sufficiently greater in cross section than the orifices so that the jets from the orifices, at showerbathwater- Y supplyrpressures sufiicient to cause the water to issue as jets from the orifices, respectively, can pass through associated passagesin the cap free .from contact withthe. peripheral wall of'their associated passages in the cap, said orifice-plate being so, thin and the entry edge of the-orifices being so sharp that eachjet, under, the-said pressure of a shower bath water supply, in passing. through its orifice; remains out of contact with the peripheral wall: ofits orifice-from the outer surface of the .plate substantiallyto the innervsurface of the plate, and outofcontact' with the peripheral walls of the cap passages, and extends axially of its orifice for a material distance beyond the cap, and baffle means interposed between the'inlet passage and the innermost face portions of the plate for causing the water to reach the orifices with a direction of flow predominantly endwise of the orifices, thereby to reduce the turbulence in the jets. v

3. A shower head comprising a hollow body adapted for connection to a shower bath water supply pipe and having an inlet passage and a discharge passage, a readily detachable closure means detachably connected to the body and covering the outlet of the passage, said closure means having jet passages therethrough, orifice plate means of thin, relatively stifi, flexible sheet material at the inner face of the cap and overhanging the margins of the inlet ends of the jet passages, said orifice plate means having water jet orifices therethrough, each orifice having a smooth entering edge, said orifices being related to the jet passages so as to be operable at household water pressures sufiicient to cause the water to issue as jets from the orifices, respectively, to discharge jets of water through the jet passages, respectively, in spaced relation to the peripheral walls of the associated jet passages, and readily removable baffle means removably secured in the body and located between the inlet passage and the surface portions of the orifice plate means which are innermost in a direction endwise of the body, for causing the water to flow to the innermost face portions of the orifice plate means generally axially of the orifices so as to reduce turbulence in the jets issuing from the orifices.

4. A shower head according to claim 3 characterized in that said orifice plate means is of organic synthetic plastic whereby the deposit thereon of solute from the water is reduced.

5. A shower head comprising a hollow body member adaptedv for connection to a shower bath water supply pipe and having a single discharge passage, a cap member detachably connected tothe. body member and covering the outlet of the passage and a plurality ofjet passages therethrough, an orifice plate in the form of a single sheet of thin, stiff, flexible sheet material detachably interposed between the body and cap member and covering the outlet of the discharge passage, said plate being sufliciently flexible to be flexed by shower bath water supply pressures which are suflicient to cause the water to issue as jets from said orifices, respectively, said plate having a plurality of circular water jet orifices therethrough, each of said orifices having an accurate, smooth, edge at its inlet end, resilient means rendered operative by connecting the cap member to the body member to engage and yieldably hold the margin of the plate so that the plate can flex and bear against the inner face of the cap member when subjected to said household water pressure.

6. A shower head comprising a hollow body adapted for connection to a shower bath water supply pipe and having a single discharge passage, a cap detachably connected to the body and covering the outlet of the passage and having a plurality of jet passages therethrough, an orifice plate in the form of a single sheet of thin, stiff, flexible sheet material detachably interposed between the body and cap and covering the outlet of the discharge passage, said plate'havinga plurality of circular water jet orifices therethrough, each of said orifices having an accurate, smooth, burrless, edge at its inlet end, said body having an annular seating area, said cap having an annular seating area facing generally toward the first seating area, said orifice plate having an annular margin alongside the seating area of the cap,

a single ring seal engaging said annular seating areas and margin and held by the cap in sealing relation thereto, and thereby constraining all water to discharge through 8 the orifice plate in a condition substantially free from turbulence.

- 7. A shower head comprising a hollow body adapted for connection to a shower bath water supply pipe and having an inlet passage and a discharge passage, a readily detachable cap covering the outlet of the discharge passage and havinga multiplicity of passages therethrough from its inner face to its outer face, an orifice plate of thin relatively stifi but flexible sheet material overlying the inner face of the cap and readily detachable relative to the body and having a plurality of water jet orifices therein which have smooth entering edges and which are aligned with the passages of the cap so as to discharge therethrough, the cap passages being sufiiciently greater in cross section than the orifices so that the jets from the orifices, at shower bath water supply pressures which are sufiicient to cause the water to issue from the orifices as jets, respectively, can pass through associated passages in the cap free from contact with the peripheral wall of their associated passages in the cap, baflie means interposed between the inlet passage and the orifice plate and spaced from the orifice plate for reducing the turbulence of the stream of water at the outlet side of the baffle means as compared to the stream at the inlet side of the baffle means for causing the water flowing to the orifices to reach the orifices with a direction of flow predominantly endwise of the orifices and thereby reduce the turbulence in the jets issuing from the orifices.

8. A shower head comprising a hollow body adapted for connection to a shower bath water supply pipe and having an inlet passage and a discharge passage, a readily detachable cap covering the outlet of the discharge passage and having a multiplicity of passages therethrough from its inner face to its outer face, an orifice plate of thin, relatively stiff but flexible sheet material overlying the inner face of the cap and readily detachable rela-' tive to the body and having a plurality of water jet orifices therein which have smooth entering edges and which are aligned with the passages of the cap so as to discharge therethrough, the cap passages being sufiiciently greater in cross section than the orifices so that the jets from the orifices, at shower bath water supply pressures which are suificient to cause the water to issue from the orifices as jets, can pass through the associated passages in the cap free from contactwith the peripheral wall of their associated passages in the cap, means interposed between the inlet passage and the inner face of the orifice plate for causing the water flowing to the orifices to reach the orifices with a direction of flow pre-' dominantly endwise of the orificesand thereby reduce. the turbulence in the jets issuing from the orifices, said means including a disc having an annular seating area about one end, said body having an annular seating area alongside the seating area of the disc, said cap having an annular seating area facing generally toward the first two seating areas, said orifice plate having an annular margin alongside the seating area of the cap, and a single 0 ring seal engaging all of said annular seating areas and margin and held by the cap in sea-ling relation thereto, and thereby constraining all water to pass through the baflie means enroute to the inlet side of the orifice plate and to discharge through the orifice plate in a condition substantially free from turbulence.

References Cited in the file of this patent UNITED STATES PATENTS 1,334,911 Lampkin Mar. 23, 1920 1,529,531 Young Mar. 10, 1925 1,891,720 McCurdy et al Dec. 20, 1932 2,652,283 Roop Sept. 15, 1953 2,733,570 MacPherson Feb. 7, 6

,7 FOREIGN PATENTS I 9,875 Great Britain 1901 

